ADS1299-4: Internal oscillator frequency is out out of spec at 25 degree Celsius.

Kazuya Nakai59

Part Number: ADS1299-4
Other Parts Discussed in Thread: ADS1299

Hello guys,

One of my customers uses ADS1299-4 for their current product.
They found 2 pcs of ADS1299-4 which data output rate is out of spec at their production test stage.
(Total number of the production is 50 sets. One ADS1299-4 is used per 1set.)

They use the device internal clock for ADS1299-4 data conversion.
Also they measured internal frequency (Typ=2.048MHz, Min/Max=0.5% a 25degree C) at CLK terminal
with CLKSEL terminal=H and CLK_EN bit (bit 5) in CONFIG1 register when Ta is 25 degree C.
As the result,
No.1 failed device = 2.062MHz(+0.7%)
No.2 failed device = 1.961MHz(-4.2%)

At this moment, they have the following questions.
Could you please give me your reply?

Q1.
Are these No.1 and 2 device out of spec? (Is the measuring way correct?)

Q2.
Which case is this phenomenon (internal clock becomes out of spec) happened at?
(This device were delivered in September of 2022. They opened vacuum pack 9 hours before soldering.)

Q3.
Is there any way to trim the clock frequency to 2.048MHz?

Your reply would be much appreciated.

Best regards,
Kazuya.

over 2 years ago

0 ChienChun Yang over 2 years ago

TI__Mastermind 19815 points

Hi,

May I know which customer is this? If cannot be disclosed in public, I will reach out to you via email.

-------------

According to ADS1299 datasheet page 10

Internal clock accuracy

@TA = +25°C accuracy is ±0.5%

@TA = –40°C to +85°C accuracy is ±2.5%

and

page 27

"The internal oscillator is trimmed for accuracy at room temperature. Accuracy varies over the specified temperature range"

-----------------------

May I ask how do they setup and measure the internal clock oscillator frequency? And, how long do they operate and measure? Do they keep monitoring the device's temperature?

As the device keep operating, the temperature may change; thus, could affect the accuracy a little bit.

Thanks

0 Kazuya Nakai59 over 2 years ago in reply to ChienChun Yang

Guru 21805 points

Hi ChienChun,

Thank you very much for your reply.

I can't disclose my customer name.
So could you please send me your e-mail?

And I think No.2 failed device oscillator frequency exceeded the spec obviously.
Have you ever been seen internal oscillator frequency shift like this?

Thank you again and best regards,
Kazuya.

0 ChienChun Yang over 2 years ago in reply to Kazuya Nakai59

TI__Mastermind 19815 points

Hi,

I will send you email

Thanks

0 Kazuya Nakai59 over 2 years ago in reply to ChienChun Yang

Guru 21805 points

Hi ChienChun,

I received your e-mail.
I will reply you after I receive the information from the customer.

Thank you and best regards,
Kazuya.

0 ChienChun Yang over 2 years ago in reply to Kazuya Nakai59

TI__Mastermind 19815 points

Thanks. please let me know.

Let's stay in email discussion.

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ADS1299-4: Internal oscillator frequency is out out of spec at 25 degree Celsius.